Vania



I No. 606,754. Patented July 5, i898.

' E. ARMSTRONG.

STUFFING BOX. (Applicatipn fiIed.Ma1-. 25, 1898.)

(N0 Model.)

7w WITNESSES:

94 {V lNVENTOR:

m MMaw UNITED STATES,

PATENT OFFICE.

ERNEST ARMSTRONG, OF CAMDEN, NEW JERSEY, ASSIGNOR TO JOHN S.

LATTA AND JAMES J. MULOONROY, OF PHILADELPHIA, PENNSYL- VANIA.

SPECIFICATION forming partof Letters Patent No. 606,754, dated July 5,1898. Application filed March 25, 1898. Serial No. 675,086. (No model.)

' citizen of the United States, residing in the city of Camden, in thecounty of Camden and State of New Jersey, have invented certain new anduseful Improvements in Stuffing- Boxes, of which the following is aspecification.

My invention relates to stuffing boxes em-v ployed in connection withthe piston rods of driver brakes, air and vacuum pumps, and

similar devices, and its objectis the provision of a packing of asimple, inexpensive, efficient, and durable, character.

In the accompanying drawing I show and herein I describe, a good form ofa convenient embodiment of my invention, the particular subject-matterclaimed as novel being hereinafter definitely set forth.

In the accompanying drawing, which is a View in central, sectional,elevation, I illustrate my invention as employed in connection with anair or pneumatic piston rod of a wellknown character. 7 v

In said drawing, A is the body, and a the headplate, of a pistoncylinder; B is a piston working in said cylinder; and b a piston rodextending through an opening a in the cylinder head a.

O is the wall of a stuffing box, constituted by a boss erected upon andpreferablyintegral with the body of the cylinder head,and concentricallydisposed with respect to the pistonrod. This stuffing box embodies acountersink c, concentric with the opening a and preferably undercut soas to be somewhat pear-shaped, so to speak,the distance betweenthe'circumferential surface indicated by the points 0cw being slightlygreater than the distance between the surface indicated by the pointsy-y.

D isapacking ring of rubber, the inner face or bore of which iscylindric and the exterior face of which is convex and approximatelysemi-cylindric. The longest circumference,

or highest point, soto speak, of said convex surface, while inthe'v'icinity of the central transverse plane -of the ring, ispreferably somewhat to one side thereof, to the end that the exterior ofthe ring-may be adapted to fitaccurately within the basal portion of thecountersunk opening in the stuffing box.

the end portion of the packing ring.

The normal diameter of the bore of the packing ring D is considerablyless than the diameter of the piston rod b on which said ring is seated,and the exterior diameter of said ring is normally somewhat less thanthe diameter of the countersunk opening 0 referred to, with the resultthat when said ring is threaded upon said piston rod it is considerablyexpanded so that it will not only hug the rod very tightly but also beso enlarged that its outer face will be forced into intimate contactwith the inner face of the countersink a.

E is an annular gland of any preferred material, seated within the outerend of the countersunk stuffing lbox,"the outer face of which isconveniently fiat and its inner face conformed to approximately fit orconform to F is a cap adapted tobe screwed upon the top of the shiftingbox, and so proportioned and applied that when screwed home it will bearagainst the gland, with the result that the latter will bear against thepacking ring and tend to shorten and further expand it against the .wallof the countersink of the stuffing box.

Having thus described claim In combination ':a piston rod or similardevice,-a stuffing box through which said rod extends and which embodiesan annular pearshaped undercut recess of greater diameter than saidrod,-a packing ring of rubber mounted on said rod, the interior diameterof which is normally less than the diameter of the rod and the exteriordiameter of which is normally less than the diameter of said opening, sothat when said ring is forced upon said rod it will be expanded againstthe inner face of said opening,and means for maintaining said ring inposition with-the said stuffing box,substantially as set forth I Intestimony that I claim the foregoing as my invention I have hereuntosigned my name this 1st day of March, A. D1898.

ERNEST ARMSTRONG.

my invention, I

In presence of--- WALTER 0. Poem, F. NORMAN DIXON.

